Free Standing Riser System Buoyancy Stabilization
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Solution Overview
Problem
Existing free standing riser systems for subsea petroleum production require vessels with derricks and compensators for handling the upper section of the riser, limiting their practicality and increasing operational costs, as they often necessitate anchored vessels and complex installation processes, especially for Long Duration Tests and Early Production Systems.
Innovation Solution
A free standing riser system with interconnected joints, a subsea intervention unit, and an umbilical line, where the riser is maintained in an erect position by a buoy assembly and connected to a Floating Production Unit (FPU) via a flexible jumper, allowing for easy installation, maintenance, and adaptation to different water depths without the need for a vessel with a derrick, using inflatable buoys for variable buoyancy and a swivel device to manage torsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a vessel with derrick and compensator is used for handling the upper section of the riser, then the riser can be stabilized and handled, but the operational costs increase and the system complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for vessel-based derrick and compensator systems by implementing a self-contained free-standing riser system. The riser is designed to be stable on its own through buoyant forces and gravitational forces acting on the riser structure itself, removing the requirement for external vessel support equipment.
Solution Approach 2:
The riser system is designed to be self-stabilizing through its own structural properties. The buoyant force from the upper section and the gravitational force from the lower section create a self-balancing system that maintains vertical stability without requiring external vessel-based stabilizing equipment.
2Ease of manufacture
If a rig vessel with derrick is used for installation, then the riser can be installed and handled, but the operational costs increase
Solution Approach 1:
The patent removes the requirement for rig vessel-based installation by designing a free-standing system that can be deployed without complex vessel equipment. The riser is lowered into position and stabilized through its own buoyant and gravitational forces, eliminating the need for expensive rig vessel operations.
Solution Approach 2:
The system uses simpler, less expensive components that can be easily deployed and retrieved. The free-standing riser configuration allows for cost-effective installation and operation compared to permanent rig vessel-based systems, making it economically viable for temporary production operations.
3Stability of the object's composition
If anchored vessels are used with the riser system, then the riser can be positioned, but the adaptability to different water depths and locations is reduced
Solution Approach 1:
The system transitions from static anchored positioning to dynamic free-standing positioning. The riser is designed to adapt to different water depths and locations through its buoyant and gravitational balance, allowing it to self-adjust to various operational conditions without requiring anchoring systems.
Solution Approach 2:
The free-standing riser system is designed to be universally applicable across different water depths and locations. The same basic riser configuration can operate in various environments by adjusting the balance of buoyant and gravitational forces, eliminating the need for location-specific anchoring systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system enables efficient subsea petroleum production and maintenance without the need for a rig vessel, reduces operational costs, and allows for easy deployment and retrieval of the riser, facilitating Long Duration Tests and Early Production Systems in various water depths up to 3,000 meters.
Implementation Method 1
the riser being maintained in an erect, substantially vertical position by a buoy assembly that encloses the upper-end of the riser
Data Source
AI summary
A free standing riser system includes a riser, a subsea intervention unit, and an umbilical line. The riser includes interconnected joints linked to one another, a lower-end of the riser being coupled to a wellhead and an upper-end of the riser enclosed in a buoy assembly, including a terminal, the riser being maintained in an erect, substantially vertical position. The subsea intervention unit is provided above the riser, and includes three connections: one connection to the terminal of the riser, one connection to a flexible jumper that is connected to a FPU, and one connection that provides a vertical conveyance to an intervention rig.